Other life in the Solar system?

[Sickle]

It is unlikely to think that out there in our/other galaxies that life may also be... Well, living. Earth can't be the only planet in the universe to have the right environment to sustain life, there may be more, some closer than you think. Life can also Adapt to the harsh conditions and may live off other elements. Earth has shown us that is possible.

But I personally think our best chance of finding more life in our Solar System would be Europa; one of Jupiter's moons. Thanks to the Voyager probes, We know the Moon, Europa, to be covered in what looks like Ice. And we believe that under that ice is Oceans of liquid water. I think if anywhere, that is the place to look. However I also think that Titan (Saturn's moon) May also one day host life.

Where do you think Could also host life; except Earth, in the solar system and why?

[SargeRho]

I think Venus, Mars, Europa, Titan, Callisto and perhaps Enceladus have life on them.

[Motokid600]

What's interests me about Europa isn't just what's under the ice. In between what looks like cracks in the ice theres.. red stuff. So we may not even know it, but we couldve been staring at life the entire time in every picture of Europa. Red algae that takes refuge from the radiation from both Jupiter and the sun perhaps?

[lajoswinkler]

Mercury is by all means dead, like the Moon.Venus has too acidic clouds even in the parts where the temperature and pressure can cover life. Its relative humidity is pathetic, too. So, highly unlikely there's anything floating in its clouds. The surface is of course, dead. Nothing can survive it.Mars might host survived (if they ever existed) chemosynthetic bacteria-like organisms deep below its ground and that's it. Ceres also... maybe.Europa is the prime candidate. Jovian satellites with high content of water could all harbour underground lakes which might contain simple life. Their surfaces are dead. Titan's surface is dead. It's too cold.

What's interests me about Europa isn't just what's under the ice. In between what looks like cracks in the ice theres.. red stuff. So we may not even know it, but we couldve been staring at life the entire time in every picture of Europa. Red algae that takes refuge from the radiation from both Jupiter and the sun perhaps?

I've forgot the name, but those are products of UV light destroying stuff... Let me get back later with more info. Edited September 13, 2013 by lajoswinkler

[Sickle]

Titan isn't dead, it's young. It has volcanoes, active ones too. It's almost as if looking at Titan is looking at a young Earth. Don't forget Ganymede; It has an atmospehere with traces of Oxygen.

[lajoswinkler]

I'm not talking about the geology. This is a thread about life. Titan's surface is dead. It has cryogenic conditions and no polar solvents, therefore biochemistry is ruled out.

Every object with surface ice will have traces of oxygen because of photolysis of water.

[Albert VDS]

Well life needs 3 things water, energy and chemicals to create life.

Carbon, nitrogen, hydrogen and oxygen are abundant in the universe.

It's suggested that it could exist in Venus upper atmosphere, which has water vapor and huge amount of energy as seen by the thunderstorms.

I think for Mars it's just a matter of time and looking in the right places to find past or current life. It has water and geothermal energy.

Europa has the highest chance of life with in it's oceans. It has liquid oceans under the ice and thermal vents.

Same for Enceladus.

Titan could have life which requires liquid methane instead of water.

It would even be possible to find it on comets.

[lajoswinkler]

Motokid600, the red stuff is composed of stuff called tholin.

Albert VDS, liquid methane is a cryogenic liquid. It's absolutely nonpolar and can not enter any interactions with stuff. No interactions, no life.

[Kryten]

You can't just mix CHON together and expect to get life, you need to have plausible precursor molecules, probably RNA bases. RNA bases are known to be reasonably common, showing up frequently in chondrite meteorites, but the formation requires UV irradiation of simpler organics, which is not good for the prospects on places like enceladus' ocean with minimal exposure to the outside environment.

[Albert VDS]

Albert VDS, liquid methane is a cryogenic liquid. It's absolutely nonpolar and can not enter any interactions with stuff. No interactions, no life.

Scientists Discover Massive Methane-Based Ecosystem

Mussels can survive in seeps through chemosynthesis, a process that utilizes bacteria in their gills to turn methane into energy.

There are also methane eating bacteria which use their self created oxygen.

Carbon dioxide is non-polar too and we all know trees eat carbon dioxide.

What is Consuming Hydrogen and Acetylene on Titan?

You can't just mix CHON together and expect to get life, you need to have plausible precursor molecules, probably RNA bases. RNA bases are known to be reasonably common, showing up frequently in chondrite meteorites, but the formation requires UV irradiation of simpler organics, which is not good for the prospects on places like enceladus' ocean with minimal exposure to the outside environment.

That's assuming that it's based on RNA and DNA.

Breakthrough in search for alien life as scientists manufacture DNA-like molecule which can transmit genetic material

A team from the University of Cambridge managed to manufacture synthetic XNAs (xeno-nucleic acids) which mimic some of the properties of DNA and RNA.

The truth is we don't know what alien lifeforms use to encode genetic instructions.

Life on Earth only proofs that RNA and DNA works to create life, but that doesn't mean it's the only way to create life.

Edited September 13, 2013 by Albert VDS

[Nibb31]

I think Venus, Mars, Europa, Titan, Callisto and perhaps Enceladus have life on them.

Based on what evidence ?

[lajoswinkler]

Scientists Discover Massive Methane-Based Ecosystem

There are also methane eating bacteria which use their self created oxygen.

Carbon dioxide is non-polar too and we all know trees eat carbon dioxide.

What is Consuming Hydrogen and Acetylene on Titan?

When you read about methane based ecosystems, that has absolutely nothing to do with liquid methane. Methane can be utilized by some chemosynthetic bacteria as food. They live in water and they're filled with water. That's light years away from living in liquid methane.

The temperatures we're talking about are cryogenic. The rates of reactions at such temperatures are close to zero. There is no enzymatic mechanism that could work at those temperatures. It's chemistry. It simply does not work.

I'm not talking from a Earth-centric standpoint, but from a chemistry standpoint. It's pretty much like saying that blocks of iron can think on other planets "because it's space and who knows what happens there".

Not only that, but liquid methane does not dissolve stuff into ions. I know it might be difficult to understand because I'm trying to shove several semesters worth of college into a post and I obviously can't.

Life requires a versatile molecule that can be an acid and a base, it requires intramolecular forces, and it requires activation energy. Titan is so cold that nothing happens on its surface. Not even inorganic processes. It's an empire of physical processes. Slow cryo-geology.

Its cloud layer is a different story. Plenty of organic chemistry there, creating stuff that falls down into the cold slush.

Photosynthetic autotrophs do not eat CO2. They eat bicarbonate anions which are formed when CO2 is dissolved in water. Plain CO2 is a very inert molecule.

Edited September 13, 2013 by lajoswinkler

[SargeRho]

Based on what evidence ?

Venus' upper atmosphere is similar to Earth at the surface.

Mars may have underground water.

Europa, Callisto, Titan and Enceladus have subsurface water oceans.

[Sickle]

And who is to say life on other planets/moons are to be exactly like earth, Life adapts to the conditions. We have plenty of evidence of that here on Earth.

[Motokid600]

Motokid600, the red stuff is composed of stuff called tholin.

Hm. Interesting. The diagram there shows Titan, but the red stuff on Europa is tholin as well?

Edited September 13, 2013 by Motokid600

[lajoswinkler]

And who is to say life on other planets/moons are to be exactly like earth, Life adapts to the conditions. We have plenty of evidence of that here on Earth.

I'm not talking about the variety of life forms. I'm talking about the fundamental principles of life itself.

Even if life once existed on the surface of Titan (not a single reason), it could not adapt to the current environment just like life can't exist in the stellar cores.

Hm. Interesting. The diagram there shows Titan, but the red stuff on Europa is tholin as well?

It seems that tholins are abundant in our system. Ceres, Pluto and other bodies are showing the same signature and you can get it artificially my mimicking the conditions in space.

Interesting thing is that Enceladus doesn't seem to have any, but that's probably because its cover is almost entirely made out of water ice.

[th3shameless]

i'm a strong believer in venus housing sulfer-based life in its upper atmosphere. scientists have discovered microbial life in clouds on earth(http://www.usnews.com/news/articles/2013/01/24/scientists-discover-microbial-life-in-storm-clouds), so it's a possibility.

Due to the harsh conditions on the surface, little of the planet has been explored; in addition to the fact that life as currently understood may not necessarily be the same in other parts of the universe, the extent of the tenacity of life on Earth itself has not yet been shown. Creatures known as extremophiles exist on Earth, preferring extreme habitats. Thermophiles and hyperthermophiles thrive at temperatures reaching above the boiling point of water, acidophiles thrive at a pH level of 3 or below, polyextremophiles can survive a varied number of extreme conditions, and many other types of extremophiles exist on Earth.[40] However, the temperature of the surface of Venus (over 450°C), is far beyond the extremophile range, which extends only tens of degrees beyond 100°C.

However, life could also exist outside the extremophile range in the cloudtops, and in the same way that bacteria have been found living and reproducing in clouds on Earth, it has been proposed that life could exist in the same area on Venus.[41] Microbes in the thick, cloudy atmosphere could be protected from solar radiation by the sulfur compounds in the air.[40] The solar wind may provide a mechanism for the transfer of such microbiota from Venus to Earth.[42]

The Venusian atmosphere has been found to be sufficiently out of equilibrium as to require further investigation.[40] Analysis of data from the Venera, Pioneer and Magellan missions has found the chemicals hydrogen sulfide (H2S) and sulfur dioxide (SO2) together in the upper atmosphere, as well as carbonyl sulfide (OCS). The first two gases react with each other, implying that something must produce them. In addition, carbonyl sulfide is noteworthy for being exceptionally difficult to produce through inorganic means.[41] Further, it is an often-overlooked fact that one of the early Venera probes detected large amounts of chlorine just below the Venusian cloud deck.[Why is this relevant?][43]

It has been proposed that microbes at this level could be soaking up ultraviolet light from the Sun as a source of energy, which could be a possible explanation for dark patches seen on UV images of the planet.[44][45] Large, non-spherical cloud particles have also been detected in the cloud decks. Their composition is still unknown.[40]

snipp from a wikipedia article on venus

[lajoswinkler]

The problem with Venus is that life probably never had the chance to evolve to the point where you've got cellular organisms, and life can't evolve in clouds. It needs bulk liquid environment with solid surface phases for starting catalysis.

Venus probably had oceans and there probably were the begginings of complex molecular mechanisms, but between that and extremophiles lies a huge time gap.

So Venus can have all the desirable conditions (but it doesn't - at the region of acceptable temperatures and pressures, there's lots of acid going around and we're speaking of nothing like the acid extremophiles would tolerate) but there is no reason to think anything complex ever evolved and went into the atmosphere.

Earth microbes that inhabit deep mines and clouds came long time after life began. Just because they're relatively simple compared to animals doesn't mean they've never changed.

[magnemoe]

When you read about methane based ecosystems, that has absolutely nothing to do with liquid methane. Methane can be utilized by some chemosynthetic bacteria as food. They live in water and they're filled with water. That's light years away from living in liquid methane.

The temperatures we're talking about are cryogenic. The rates of reactions at such temperatures are close to zero. There is no enzymatic mechanism that could work at those temperatures. It's chemistry. It simply does not work.

I'm not talking from a Earth-centric standpoint, but from a chemistry standpoint. It's pretty much like saying that blocks of iron can think on other planets "because it's space and who knows what happens there".

Not only that, but liquid methane does not dissolve stuff into ions. I know it might be difficult to understand because I'm trying to shove several semesters worth of college into a post and I obviously can't.

Life requires a versatile molecule that can be an acid and a base, it requires intramolecular forces, and it requires activation energy. Titan is so cold that nothing happens on its surface. Not even inorganic processes. It's an empire of physical processes. Slow cryo-geology.

Its cloud layer is a different story. Plenty of organic chemistry there, creating stuff that falls down into the cold slush.

Photosynthetic autotrophs do not eat CO2. They eat bicarbonate anions which are formed when CO2 is dissolved in water. Plain CO2 is a very inert molecule.

Thanks, had an earlier discussion about sample returns where life on Titan came up.

I was skeptical but from the wrong reasons, even if it was temprature related. Think part is that many hydrocarbons on earth are good solvents however things behave different at -150.

[lajoswinkler]

Yes, very good solvents for nonpolar molecules, but inert solvents. Hexane will dissolve petroleum jelly, oil or fat at an astounding speed, but it's all diffusion. The only forces acting here are London dispersive forces. Very weak stuff.

Whan water dissolves stuff, it reacts with them. If it's sucrose, it surrounds its oxygen atoms (-OH groups), if it's hydrogen chloride, it will rip the molecule apart. If it's protein, it will fold it.

From a chemical standpoint, water isn't that special, but when you look at life that was enabled because of water, it really becomes something remarkable. It's so abundant and so versatile in its behaviour that I can hardly imagine the possibility of life without it. There is simply no analogues for it, only very poor surrogates like liquid ammonia which boils below -30°C at 1atm. Ammonia has one free electron pair so hydrogen bonds can be formed. Problem is that finding lots of liquid ammonia is next to impossible. Whenever there are good conditions for it, there's a ton of other stuff, too.

[TheCanadianVendingMachine]

Why do you say it's too cold on the moons/planets? I mean, evolution can make it so they can live in such enviroments.

[lajoswinkler]

Evolution is not an omnipotent phenomenon. As much as it can't make organisms live in vacuum, it can't make them live in stellar cores or liquid methane. There are limits.

Life is a complex arrangement of biochemical reactions. If the conditions don't permit those reaction, there's no life.

[SargeRho]

We see life in both "too cold" and "too hot" conditions on Earth. Black Smokers melt submarine windows, but many lifeforms are pretty happy in there.

[dharak1]

As much as it can't make organisms live in vacuum, it can't make them live in stellar cores or liquid methane.

Can't animals like tardigrades survive in vacuum?

[Albert VDS]

When you read about methane based ecosystems, that has absolutely nothing to do with liquid methane. Methane can be utilized by some chemosynthetic bacteria as food. They live in water and they're filled with water. That's light years away from living in liquid methane.

I posted the link to show that life does live on non-polar molecules. Of course it doesn't live on liquid methane, because the tree of life on Earth is water based.

Photosynthetic autotrophs do not eat CO2. They eat bicarbonate anions which are formed when CO2 is dissolved in water. Plain CO2 is a very inert molecule.

That's like saying; "Humans don't eat hamburgers, they oxidize carbohydrates."

The temperatures we're talking about are cryogenic. The rates of reactions at such temperatures are close to zero. There is no enzymatic mechanism that could work at those temperatures. It's chemistry. It simply does not work.

But there is still movement, it's about 100 °C above absolute zero. It would be a very slow life form, but thats no reason for it not to work. Again, plants are a very slow life form.

I'm not talking from a Earth-centric standpoint, but from a chemistry standpoint. It's pretty much like saying that blocks of iron can think on other planets "because it's space and who knows what happens there".

So to you a thinking block of iron is as likely as liquid methane base life form.

Not only that, but liquid methane does not dissolve stuff into ions. I know it might be difficult to understand because I'm trying to shove several semesters worth of college into a post and I obviously can't.

Life requires a versatile molecule that can be an acid and a base, it requires intramolecular forces, and it requires activation energy. Titan is so cold that nothing happens on its surface. Not even inorganic processes. It's an empire of physical processes. Slow cryo-geology.

Its cloud layer is a different story. Plenty of organic chemistry there, creating stuff that falls down into the cold slush.

Isn't it more like; Polar molecules dissolve polar molecules and nonpolar molecule only nonpolar molecules?

What I'm wondering about is Chris McKay(and other astrobiologists) wrong about his hypothesis?

Of course hes not right because hes Chris McKay, but why would an astrobiologist propose such an idea?